19 results on '"Alexandra L Farrall"'
Search Results
2. The International Vitreoretinal B-Cell Lymphoma Registry: a protocol paper
- Author
-
David J Wilson, Valérie Touitou, Justine R Smith, Manabu Mochizuki, Hiroshi Takase, Steven Yeh, Alexandra L Farrall, H Nida Sen, Daniel V Vasconcelos-Santos, Joke H de Boer, Ninette H ten Dam-van Loon, Janet L Davis, Anthony J Hall, and Mark H B Radford
- Subjects
Medicine - Abstract
Introduction Vitreoretinal lymphoma is a rare ocular cancer with high morbidity and mortality despite treatment. Diagnosis by cytopathology is often delayed, and various molecular and image-based investigations have been developed. Diverse treatments are used, but there is a limited medical evidence to differentiate their effectiveness. We designed an international registry that would collect diagnostic, treatment and outcomes data, to establish new evidence for the management of this cancer.Methods and analysis The International Vitreoretinal B-Cell Lymphoma Registry will accrue data retrospectively for individuals aged 18 years or older, diagnosed with new or recurrent vitreoretinal B-cell lymphoma on or after 1 January 2020. A steering committee of subspecialised ophthalmologists identified 20 key clinical data items that describe patient demographics, tissue involvements, diagnostic testing, ocular and systemic treatments and treatment complications, and visual acuity and survival outcomes. Customised software was designed to permit collection of these data across a single baseline and multiple follow-up forms. The platform collects data without identifiers and at 3 month reporting intervals. Outcomes of the project will include: (1) descriptions of clinical presentations, and diagnostic and therapeutic preferences; (2) associations between clinical presentations, and diagnostics and treatments, and between diagnostics and treatments (assessed by ORs with 95% CIs); and (3) estimations of rates of vision loss, and progression-free and overall survival (assessed by Kaplan-Meier estimates).Ethics and dissemination The registry has received Australia-wide approval by a national human research ethics committee. Sites located outside Australia are required to seek local human research ethics review. Results generated through the registry will be disseminated primarily by peer-reviewed publications that are expected to inform clinical practice, as well as educational materials.
- Published
- 2022
- Full Text
- View/download PDF
3. Study protocol of a phase 1 clinical trial establishing the safety of intrapleural administration of liposomal curcumin: curcumin as a palliative treatment for malignant pleural effusion (IPAL-MPE)
- Author
-
Christos Stelios Karapetis, Sonja Klebe, Ashleigh Jean Hocking, Alexandra L Farrall, Sarah Newhouse, Peter Sordillo, Kim Greco, and Brendan Dougherty
- Subjects
Medicine - Abstract
Introduction This is a phase 1, open-label, single-centre, uncontrolled, dose-escalation study to evaluate the feasibility, tolerability and pharmacokinetic profiles of a single dose of liposomal curcumin, administered via an existing tunnelled indwelling pleural catheter (TIPC) directly to the tumour site in individuals with diagnoses of malignant pleural effusion. Primarily, we aim to determine a maximum tolerated dose of liposomal curcumin administered via this method.Methods and analysis We will use a 3+3 expanded cohort for predefined dose-escalation levels or until a predefined number of dose-limiting toxicities are reached. Participants will be administered a single dose of liposomal curcumin (LipoCurc, SignPath Pharma) via their existing TIPC as a sequential enrolling case series with the following dose cohorts: 100, 200 and 300 mg/m2. Primary endpoints are determination of the maximum tolerated dose within the predetermined dose range, and determination of the feasibility of intrapleural administration of liposomal curcumin via an existing TIPC. Secondary endpoints include determination of the safety and tolerability of intrapleural administration of liposomal curcumin, median overall survival, effects on quality of life and on feelings of breathlessness, and the pharmacokinetics and concentrations of curcumin from the plasma and the pleural fluid. Important inclusion criteria include age ≥18 years, an existing TIPC, a pleural biopsy or pleural fluid cytology-proven diagnosis of malignant pleural effusion and for whom no antitumour therapy of proven benefit is available or has been previously declined, eastern cooperative group performance status
- Published
- 2021
- Full Text
- View/download PDF
4. DNA-methylome analysis of mouse intestinal adenoma identifies a tumour-specific signature that is partly conserved in human colon cancer.
- Author
-
Christina Grimm, Lukas Chavez, Mireia Vilardell, Alexandra L Farrall, Sascha Tierling, Julia W Böhm, Phillip Grote, Matthias Lienhard, Jörn Dietrich, Bernd Timmermann, Jörn Walter, Michal R Schweiger, Hans Lehrach, Ralf Herwig, Bernhard G Herrmann, and Markus Morkel
- Subjects
Genetics ,QH426-470 - Abstract
Aberrant CpG methylation is a universal epigenetic trait of cancer cell genomes. However, human cancer samples or cell lines preclude the investigation of epigenetic changes occurring early during tumour development. Here, we have used MeDIP-seq to analyse the DNA methylome of APC(Min) adenoma as a model for intestinal cancer initiation, and we present a list of more than 13,000 recurring differentially methylated regions (DMRs) characterizing intestinal adenoma of the mouse. We show that Polycomb Repressive Complex (PRC) targets are strongly enriched among hypermethylated DMRs, and several PRC2 components and DNA methyltransferases were up-regulated in adenoma. We further demonstrate by bisulfite pyrosequencing of purified cell populations that the DMR signature arises de novo in adenoma cells rather than by expansion of a pre-existing pattern in intestinal stem cells or undifferentiated crypt cells. We found that epigenetic silencing of tumour suppressors, which occurs frequently in colon cancer, was rare in adenoma. Quite strikingly, we identified a core set of DMRs, which is conserved between mouse adenoma and human colon cancer, thus possibly revealing a global panel of epigenetically modified genes for intestinal tumours. Our data allow a distinction between early conserved epigenetic alterations occurring in intestinal adenoma and late stochastic events promoting colon cancer progression, and may facilitate the selection of more specific clinical epigenetic biomarkers.
- Published
- 2013
- Full Text
- View/download PDF
5. Supplementary Data from PWD/Ph-Encoded Genetic Variants Modulate the Cellular Wnt/β-Catenin Response to Suppress ApcMin-Triggered Intestinal Tumor Formation
- Author
-
Markus Morkel, Bernhard G. Herrmann, Ralf Herwig, Bernd Timmermann, Jiri Forejt, Marta Caparros, Susanna H.M. Sluka, Heiner Kuhl, Christina Grimm, Matthias Lienhard, and Alexandra L. Farrall
- Abstract
Supplementary Figures 1-7. Supplementary Figure 1: Assembly of the PWD genome and alignment to the C57BL/6 genome. Supplementary Figure 2: RNA-seq read assignment. Supplementary Figure 3: MeDIP-seq quality controls. Supplementary Figure 4: Histology and distribution of tumors in B6 x PWD consomic mice. Supplementary Figure 5: Transcriptome analyses identify modifier candidate genes on other chromosomes than chromosome 5. Supplementary Figure 6: Strain-specific DNA methylation on chromosome 5 is correlated to CpG availability. Supplementary Figure 7: Assessment of cell types in the intestinal crypt.
- Published
- 2023
6. Data from PWD/Ph-Encoded Genetic Variants Modulate the Cellular Wnt/β-Catenin Response to Suppress ApcMin-Triggered Intestinal Tumor Formation
- Author
-
Markus Morkel, Bernhard G. Herrmann, Ralf Herwig, Bernd Timmermann, Jiri Forejt, Marta Caparros, Susanna H.M. Sluka, Heiner Kuhl, Christina Grimm, Matthias Lienhard, and Alexandra L. Farrall
- Abstract
Genetic predisposition affects the penetrance of tumor-initiating mutations, such as APC mutations that stabilize β-catenin and cause intestinal tumors in mice and humans. However, the mechanisms involved in genetically predisposed penetrance are not well understood. Here, we analyzed tumor multiplicity and gene expression in tumor-prone ApcMin/+ mice on highly variant C57BL/6J (B6) and PWD/Ph (PWD) genetic backgrounds. (B6 × PWD) F1 APCMin offspring mice were largely free of intestinal adenoma, and several chromosome substitution (consomic) strains carrying single PWD chromosomes on the B6 genetic background displayed reduced adenoma numbers. Multiple dosage-dependent modifier loci on PWD chromosome 5 each contributed to tumor suppression. Activation of β-catenin–driven and stem cell–specific gene expression in the presence of ApcMin or following APC loss remained moderate in intestines carrying PWD chromosome 5, suggesting that PWD variants restrict adenoma initiation by controlling stem cell homeostasis. Gene expression of modifier candidates and DNA methylation on chromosome 5 were predominantly cis controlled and largely reflected parental patterns, providing a genetic basis for inheritance of tumor susceptibility. Human SNP variants of several modifier candidates were depleted in colorectal cancer genomes, suggesting that similar mechanisms may also affect the penetrance of cancer driver mutations in humans. Overall, our analysis highlights the strong impact that multiple genetic variants acting in networks can exert on tumor development.Significance:These findings in mice show that, in addition to accidental mutations, cancer risk is determined by networks of individual gene variants.
- Published
- 2023
7. Supplementary tables 1-7 from PWD/Ph-Encoded Genetic Variants Modulate the Cellular Wnt/β-Catenin Response to Suppress ApcMin-Triggered Intestinal Tumor Formation
- Author
-
Markus Morkel, Bernhard G. Herrmann, Ralf Herwig, Bernd Timmermann, Jiri Forejt, Marta Caparros, Susanna H.M. Sluka, Heiner Kuhl, Christina Grimm, Matthias Lienhard, and Alexandra L. Farrall
- Abstract
Supplementary tables 1-7. Supplementary Table 1: GSEA signatures and references (Wnt target genes are taken from the HALLMARK Signature). Supplementary Table 2: 58 differentially expressed genes on chromosome 5, B6 vs C5 APC min normal intestine. Supplementary Table 3: 116 differentially expressed genes not located on chromosome 5, B6 vs C5 APC min normal intestine. Supplementary table 4: Differentially expressed genes on chromosome 5 regulated in cis, trans, or both. Supplementary table 5: Candidate modifier genes differentially expressed between B6 or PWD chromosome 5. Supplementary Table 6: Polymorphisms in human orthologs of mouse genes located on chromosome 5, polymorphic between B6 and PWD, and expressed in the intestine. Supplementary Table 7: PWD polymorphisms on chr5 in genes that are expressed in the intestine and/or in adenoma.
- Published
- 2023
8. Incidence and survival of ocular diffuse large B‐cell lymphomas
- Author
-
Alexandra L. Farrall and Justine R. Smith
- Subjects
Ophthalmology ,General Medicine - Published
- 2022
9. PWD/Ph-Encoded Genetic Variants Modulate the Cellular Wnt/β-Catenin Response to Suppress ApcMin-Triggered Intestinal Tumor Formation
- Author
-
Bernhard G. Herrmann, Bernd Timmermann, Susanna H. M. Sluka, Jiri Forejt, Ralf Herwig, Heiner Kuhl, Marta Caparros, Matthias Lienhard, Markus Morkel, Christina Grimm, Alexandra L. Farrall, University of Zurich, Herrmann, Bernhard G, and Morkel, Markus
- Subjects
0301 basic medicine ,Genetics ,Cancer Research ,Wnt signaling pathway ,Chromosome ,Cancer ,610 Medicine & health ,Biology ,medicine.disease ,Penetrance ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Oncology ,10036 Medical Clinic ,030220 oncology & carcinogenesis ,Catenin ,Gene expression ,DNA methylation ,Genetic predisposition ,medicine ,2730 Oncology ,1306 Cancer Research - Abstract
Genetic predisposition affects the penetrance of tumor-initiating mutations, such as APC mutations that stabilize β-catenin and cause intestinal tumors in mice and humans. However, the mechanisms involved in genetically predisposed penetrance are not well understood. Here, we analyzed tumor multiplicity and gene expression in tumor-prone ApcMin/+ mice on highly variant C57BL/6J (B6) and PWD/Ph (PWD) genetic backgrounds. (B6 × PWD) F1 APCMin offspring mice were largely free of intestinal adenoma, and several chromosome substitution (consomic) strains carrying single PWD chromosomes on the B6 genetic background displayed reduced adenoma numbers. Multiple dosage-dependent modifier loci on PWD chromosome 5 each contributed to tumor suppression. Activation of β-catenin–driven and stem cell–specific gene expression in the presence of ApcMin or following APC loss remained moderate in intestines carrying PWD chromosome 5, suggesting that PWD variants restrict adenoma initiation by controlling stem cell homeostasis. Gene expression of modifier candidates and DNA methylation on chromosome 5 were predominantly cis controlled and largely reflected parental patterns, providing a genetic basis for inheritance of tumor susceptibility. Human SNP variants of several modifier candidates were depleted in colorectal cancer genomes, suggesting that similar mechanisms may also affect the penetrance of cancer driver mutations in humans. Overall, our analysis highlights the strong impact that multiple genetic variants acting in networks can exert on tumor development. Significance: These findings in mice show that, in addition to accidental mutations, cancer risk is determined by networks of individual gene variants.
- Published
- 2021
10. Eye involvement in primary central nervous system lymphoma
- Author
-
Alexandra L. Farrall and Justine R. Smith
- Subjects
medicine.medical_specialty ,Lymphoma ,genetic structures ,Eye disease ,Global Health ,Malignancy ,Retina ,Central Nervous System Neoplasms ,03 medical and health sciences ,0302 clinical medicine ,hemic and lymphatic diseases ,Internal medicine ,Prevalence ,medicine ,Humans ,business.industry ,Eye Neoplasms ,Incidence (epidemiology) ,Primary central nervous system lymphoma ,medicine.disease ,eye diseases ,Vitreous Body ,Ophthalmology ,Cohort ,030221 ophthalmology & optometry ,sense organs ,business ,Diffuse large B-cell lymphoma ,030217 neurology & neurosurgery ,Cohort study - Abstract
Primary central nervous system lymphoma (PCNSL) may manifest initially in the eye (termed vitreoretinal lymphoma or VRL) or in non-ocular CNS compartments, or in both. The nature of the onset of PCNSL implies two clinical specialists - ophthalmologists and neuro-oncologists - independently may assess the primary presentation of this rare malignancy. Clinically relevant perspectives on expectations of PCNSL manifestation in both ocular and non-ocular CNS compartments would help inform management practices in each specialty, which should impact clinical outcomes. A recent increase in the number of published PCNSL cohort studies provides new opportunity to review the current prevalence rates of ocular involvement, and the timing of this involvement over the course of disease. In PCNSL cohorts defined by non-ocular CNS compartment involvement, with or without ocular involvement (termed "PCNSL ± ocular involvement" cohorts), mean rates of concomitant VRL at diagnosis, or at any time during the course, are 10% and 16%, respectively. Only a few individuals within this cohort group present with exclusive eye disease (
- Published
- 2020
11. A case of combined hamartoma of the retina and retinal pigment epithelium with response to intravitreal ganciclovir injection
- Author
-
Justine R. Smith, Alexandra L. Farrall, Lisia Barros Ferreira, and João M. Furtado
- Subjects
medicine.medical_specialty ,genetic structures ,medicine.drug_class ,business.industry ,General Medicine ,medicine.disease ,Dermatology ,eye diseases ,Intraocular inflammation ,Ophthalmology ,Infectious uveitis ,medicine ,Corticosteroid ,Eye disorder ,Biological response modifiers ,business ,Large group ,Uveitis - Abstract
Uveitis is a broad term that refers to a large group of eye disorders categorized by intraocular inflammation, a leading cause of visual impairment. Historically, treatment of noninfectious uveitis has depended on corticosteroid drugs. Owing to the myriad of side effects caused by corticosteroids, immunomodulatory therapy has become the preferred treatment for chronic noninfectious intraocular inflammation. Recently, biological response modifiers have established a new era in uveitis therapy, with the range of targets continuing to expand. In this review, we aimed to convey up-to-date information on the treatment of noninfectious uveitis to the general ophthalmologist.
- Published
- 2022
12. Treatment of noninfectious uveitis
- Author
-
Lisia Barros Ferreira, Alexandra L. Farrall, João M. Furtado, and Justine R. Smith
- Subjects
Uveitis ,Inflammation ,Ophthalmology ,genetic structures ,Immunomodulatory therapy ,RE1-994 ,Biologics ,eye diseases ,Noninfectious uveitis - Abstract
Uveitis is a broad term that refers to a large group of eye disorders categorized by intraocular inflammation, a leading cause of visual impairment. Historically, treatment of noninfectious uveitis has depended on corticosteroid drugs. Owing to the myriad of side effects caused by corticosteroids, immunomodulatory therapy has become the preferred treatment for chronic noninfectious intraocular inflammation. Recently, biological response modifiers have established a new era in uveitis therapy, with the range of targets continuing to expand. In this review, we aimed to convey up-to-date information on the treatment of noninfectious uveitis to the general ophthalmologist.
- Published
- 2021
13. The International Vitreoretinal B-Cell Lymphoma Registry: a protocol paper
- Author
-
Justine R Smith, Alexandra L Farrall, Janet L Davis, Joke H de Boer, Anthony J Hall, Manabu Mochizuki, H Nida Sen, Hiroshi Takase, Ninette H ten Dam-van Loon, Valérie Touitou, Daniel V Vasconcelos-Santos, David J Wilson, Steven Yeh, and Mark H B Radford
- Subjects
Vitreous Body ,Lymphoma, B-Cell ,Eye Neoplasms ,Retinal Neoplasms ,Humans ,Registries ,General Medicine ,Neoplasm Recurrence, Local ,Retrospective Studies - Abstract
IntroductionVitreoretinal lymphoma is a rare ocular cancer with high morbidity and mortality despite treatment. Diagnosis by cytopathology is often delayed, and various molecular and image-based investigations have been developed. Diverse treatments are used, but there is a limited medical evidence to differentiate their effectiveness. We designed an international registry that would collect diagnostic, treatment and outcomes data, to establish new evidence for the management of this cancer.Methods and analysisThe International Vitreoretinal B-Cell Lymphoma Registry will accrue data retrospectively for individuals aged 18 years or older, diagnosed with new or recurrent vitreoretinal B-cell lymphoma on or after 1 January 2020. A steering committee of subspecialised ophthalmologists identified 20 key clinical data items that describe patient demographics, tissue involvements, diagnostic testing, ocular and systemic treatments and treatment complications, and visual acuity and survival outcomes. Customised software was designed to permit collection of these data across a single baseline and multiple follow-up forms. The platform collects data without identifiers and at 3 month reporting intervals. Outcomes of the project will include: (1) descriptions of clinical presentations, and diagnostic and therapeutic preferences; (2) associations between clinical presentations, and diagnostics and treatments, and between diagnostics and treatments (assessed by ORs with 95% CIs); and (3) estimations of rates of vision loss, and progression-free and overall survival (assessed by Kaplan-Meier estimates).Ethics and disseminationThe registry has received Australia-wide approval by a national human research ethics committee. Sites located outside Australia are required to seek local human research ethics review. Results generated through the registry will be disseminated primarily by peer-reviewed publications that are expected to inform clinical practice, as well as educational materials.
- Published
- 2022
14. Treatment of noninfectious uveitis
- Author
-
Lisia Barros, Ferreira, Alexandra L, Farrall, João M, Furtado, and Justine R, Smith
- Subjects
Inflammation ,Uveitis ,Adrenal Cortex Hormones ,Humans ,Immunologic Factors - Abstract
Uveitis is a broad term that refers to a large group of eye disorders categorized by intraocular inflammation, a leading cause of visual impairment. Historically, treatment of noninfectious uveitis has depended on corticosteroid drugs. Owing to the myriad of side effects caused by corticosteroids, immunomodulatory therapy has become the preferred treatment for chronic noninfectious intraocular inflammation. Recently, biological response modifiers have established a new era in uveitis therapy, with the range of targets continuing to expand. In this review, we aimed to convey up-to-date information on the treatment of noninfectious uveitis to the general ophthalmologist.
- Published
- 2020
15. PWD/Ph-Encoded Genetic Variants Modulate the Cellular Wnt/β-Catenin Response to Suppress
- Author
-
Alexandra L, Farrall, Matthias, Lienhard, Christina, Grimm, Heiner, Kuhl, Susanna H M, Sluka, Marta, Caparros, Jiri, Forejt, Bernd, Timmermann, Ralf, Herwig, Bernhard G, Herrmann, and Markus, Morkel
- Subjects
Intestines ,Male ,Mice, Inbred C57BL ,Wnt Proteins ,Mice ,Cell Transformation, Neoplastic ,Genes, APC ,Mutation ,Animals ,Genetic Predisposition to Disease ,Colorectal Neoplasms ,beta Catenin - Abstract
Genetic predisposition affects the penetrance of tumor-initiating mutations, such as APC mutations that stabilize β-catenin and cause intestinal tumors in mice and humans. However, the mechanisms involved in genetically predisposed penetrance are not well understood. Here, we analyzed tumor multiplicity and gene expression in tumor-prone
- Published
- 2020
16. Changing Incidence and Survival of Primary Central Nervous System Lymphoma in Australia: A 33-Year National Population-Based Study
- Author
-
Justine R. Smith and Alexandra L. Farrall
- Subjects
0301 basic medicine ,Cancer Research ,medicine.medical_specialty ,Pediatrics ,Lymphoma ,diffuse large B-cell lymphoma ,lcsh:RC254-282 ,survival ,Article ,03 medical and health sciences ,0302 clinical medicine ,hemic and lymphatic diseases ,Epidemiology ,medicine ,business.industry ,Incidence (epidemiology) ,Primary central nervous system lymphoma ,Cancer ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,central nervous system ,medicine.disease ,Confidence interval ,Population based study ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,incidence ,business ,Diffuse large B-cell lymphoma - Abstract
Primary central nervous system lymphoma (PCNSL) is a rare brain cancer that remains challenging to study. Epidemiology of PCNSL in the Australian population, which is racially and ethnically diverse, has not been examined previously. Using ICD-O-3.1 Morphology and Topography Codes to identify cases, we analyzed complete datasets from the comprehensive Australian Cancer Database (1982&ndash, 2014, adults aged &ge, 20 years) to establish incidence rates and trends of PCNSL, and to define survival outcomes of individuals diagnosed with PCNSL, including the predominant diffuse large B-cell lymphoma (DLBCL) type. Age-standardized incidence of PCNSL increased by an average annual 6.8% percent over the study period, with current incidence of 0.43 (95% confidence interval, 0.41&ndash, 0.46) per 100,000 person-years, in comparison to 21.89 (21.41&ndash, 22.38) per 100,000 person-years for non-CNS lymphoma. Increase in incidence was characterized by an acute rise between 1996 and 1999, was more pronounced with increasing age, and was driven by increasing incidence of DLBCL. Overall survival for persons diagnosed with PCNSL improved significantly across the study period, with 5-year survival probability increasing from 0.21 (95% confidence interval, 0.16&ndash, 0.26) to 0.33 (0.30&ndash, 0.36), and median survival increasing from 318 to 600 days, between 1982&ndash, 1999 and 2000&ndash, 2014. Increase in survival was significantly higher for persons with DLBCL versus non-DLBCL PCNSL, but substantially lower than that for persons with non-CNS lymphoma, who had a 5-year survival probability of 0.62 (0.62&ndash, 0.62) and a median survival of 3388 days in 2000&ndash, 2014. This study links increasing incidence of PCNSL in Australia to increasing incidence of DLCBL, including in younger adults, and highlights the improving, but low, survival outcome of this cancer.
- Published
- 2021
17. Wnt and BMP signals control intestinal adenoma cell fates
- Author
-
Bernhard G. Herrmann, Pamela Riemer, Amulya Sreekumar, Christina Grimm, Marc Leushacke, Alexandra L. Farrall, and Markus Morkel
- Subjects
Adenoma ,Cancer Research ,medicine.medical_specialty ,Cellular differentiation ,Cell ,Mice, Transgenic ,Mice ,Cancer stem cell ,Spheroids, Cellular ,Internal medicine ,Tumor Cells, Cultured ,medicine ,Animals ,Intestinal Mucosa ,Autocrine signalling ,beta Catenin ,biology ,CD44 ,Wnt signaling pathway ,Cell Differentiation ,Intestinal epithelium ,Cell biology ,Gene Expression Regulation, Neoplastic ,Intestines ,Wnt Proteins ,Endocrinology ,medicine.anatomical_structure ,Oncology ,Bone Morphogenetic Proteins ,Mutation ,Neoplastic Stem Cells ,biology.protein ,Stem cell ,Signal Transduction - Abstract
Cellular hierarchies and signals that govern stemness and differentiation of intestinal adenoma cells are not well defined. In this study, we used organotypic culture to investigate the impact of β-catenin and BMP signals in cells that form intestinal adenoma in the mouse. We found that activation of β-catenin signaling by loss of APC or transgenic induction of oncogenic mutant β-catenin (Ctnnb1(mut) ) initiates the conversion of untransformed intestinal cells to tumor cells. These tumor cells display cancer stem cell (CSC) traits such as increased expression of the CSC markers Cd133 and Cd44, a high capacity for self-renewal and unlimited proliferative potential. Subsequent inactivation of transgenic Ctnnb1(mut) results in the reversion of tumor cells to normal intestinal stem cells, which immediately reinstall the cellular hierarchy of the normal intestinal epithelium. Our data demonstrate that oncogenic activation of β-catenin signaling initiates the early steps of intestinal cellular transformation in the absence of irreversible genetic or epigenetic changes. Interestingly, we found that tumor cells in culture and in adenoma produce BMP4, which counteracts CSC-like traits by initiating irreversible cellular differentiation and loss of self-renewal capacity. We conclude that the opposition of stemness-maintaining oncogenic β-catenin signals and autocrine differentiating BMP signals within the adenoma cell provides a rationale for the formation of cellular hierarchies in intestinal adenoma and may serve to limit adenoma growth.
- Published
- 2012
18. DNA-methylome analysis of mouse intestinal adenoma identifies a tumour-specific signature that is partly conserved in human colon cancer
- Author
-
Christina Grimm, Lukas Chavez, Mireia Vilardell, Alexandra L Farrall, Sascha Tierling, Julia W Böhm, Phillip Grote, Matthias Lienhard, Jörn Dietrich, Bernd Timmermann, Jörn Walter, Michal R Schweiger, Hans Lehrach, Ralf Herwig, Bernhard G Herrmann, and Markus Morkel
- Subjects
Adenoma ,Epigenomics ,lcsh:QH426-470 ,Mouse ,Polycomb-Group Proteins ,Gastroenterology and Hepatology ,Synteny ,Mice ,Model Organisms ,Genomic Medicine ,Intestinal Neoplasms ,Gastrointestinal Cancers ,Genetics ,Animals ,Humans ,Biology ,Genome ,Base Sequence ,Systems Biology ,Genomics ,Animal Models ,DNA Methylation ,digestive system diseases ,lcsh:Genetics ,Colonic Neoplasms ,Medicine ,CpG Islands ,Epigenetics ,DNA modification ,Research Article - Abstract
Aberrant CpG methylation is a universal epigenetic trait of cancer cell genomes. However, human cancer samples or cell lines preclude the investigation of epigenetic changes occurring early during tumour development. Here, we have used MeDIP-seq to analyse the DNA methylome of APCMin adenoma as a model for intestinal cancer initiation, and we present a list of more than 13,000 recurring differentially methylated regions (DMRs) characterizing intestinal adenoma of the mouse. We show that Polycomb Repressive Complex (PRC) targets are strongly enriched among hypermethylated DMRs, and several PRC2 components and DNA methyltransferases were up-regulated in adenoma. We further demonstrate by bisulfite pyrosequencing of purified cell populations that the DMR signature arises de novo in adenoma cells rather than by expansion of a pre-existing pattern in intestinal stem cells or undifferentiated crypt cells. We found that epigenetic silencing of tumour suppressors, which occurs frequently in colon cancer, was rare in adenoma. Quite strikingly, we identified a core set of DMRs, which is conserved between mouse adenoma and human colon cancer, thus possibly revealing a global panel of epigenetically modified genes for intestinal tumours. Our data allow a distinction between early conserved epigenetic alterations occurring in intestinal adenoma and late stochastic events promoting colon cancer progression, and may facilitate the selection of more specific clinical epigenetic biomarkers., Author Summary The formation and progression of tumours to metastatic disease is driven by two major mechanisms, i.e. genetic alterations that activate oncogenes or inactivate tumour suppressor genes, and changes in the epigenome that cause variations in the expression of the genetic information. A deeper understanding of the interaction between the genetic and epigenetic mechanisms is critical for the selection of tumour biomarkers and for the future development of therapies. Human tumour specimens and cell lines contain a plethora of genetic and epigenetic changes, which complicate data analysis. In contrast, mouse tumour models such as the APCMin mouse used in this study arise by a single initiating genetic mutation, yet share key traits with human cancer. Here we show that mouse adenomas acquire a multitude of epigenetic alterations, which are recurring in mouse adenoma and in human colon cancer, representing early and advanced tumours, respectively. The use of a mouse model thus allowed us to uncover a sequence of epigenetic changes occurring in tumours, which may facilitate the identification of novel clinical colon cancer biomarkers.
- Published
- 2012
19. Influence of format on in vitro penetration of antibody fragments through porcine cornea
- Author
-
Douglas J. Coster, Keryn A. Williams, Michael A. Thiel, Dianna M Hocking, Melinda N. Tea, Susan D Taylor, Alexandra L Farrall, and Helen M. Brereton
- Subjects
Laboratory Science - Extended Reports ,CD4 antigen ,genetic structures ,Swine ,Administration, Topical ,Immunoglobulin Variable Region ,Antigens, CD4 ,Cornea ,Tissue Culture Techniques ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Mice ,Immunoglobulin Fab Fragments ,Antigen ,Escherichia coli ,Animals ,Lymphocytes ,Particle Size ,biology ,Research Support, Non-U.S. Gov't ,Epithelium, Corneal ,Penetration (firestop) ,Flow Cytometry ,Australian Standard Research Classification 321016 Ophthalmology and Vision Science ,Molecular biology ,Sensory Systems ,In vitro ,eye diseases ,Rats ,Ophthalmology ,Papain ,chemistry ,CD4 Antigens ,Protein Fragment ,biology.protein ,sense organs ,Antibody ,Dimerization - Abstract
Aim: Antibody fragments, appropriately formulated, can penetrate through the ocular surface and thus have potential as therapeutic agents. The aim was to investigate the influence of protein fragment format on the kinetics and extent of ocular penetration in vitro. Methods: Immunoglobulin single chain variable domain fragments of a murine monoclonal antibody with specificity for rat CD4 were engineered with a 20 or 11 amino acid linker by assembly polymerase chain reaction, expressed in Escherichia coli and purified by chromatography. Fab fragments of the parental antibody were prepared by papain digestion. Antibody fragments were formulated with a penetration and a viscosity enhancer and were applied to the surface of perfused pig corneas for up to 10 hours in vitro. Penetration was quantified by flow cytometry on rat thymocytes. Results: 20-mer antibody fragments formed natural monomers and dimers following purification that could be separately isolated, while 11-mer fragments were dimeric. All formats of fragment (20-mer monomers and dimers, 11-mer dimers, Fab) showed penetration through the pig cornea after 6 hours of intermittent topical administration. Conclusion: Antibody fragments of different shapes and sizes can penetrate the cornea after topical administration, thereby increasing the potential of this class of proteins for topical ophthalmic use.
- Published
- 2005
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.